[PROJ] CSRS Epoch 2017.50 (NAD83)

[Javier Jimenez Shaw]

Hi

Anybody from "CSRC: California Spatial Reference Center", or a friend of a
friend?
It would be interesting if they register their CRSs in EPSG.

If anyone knows who can I contact there, it would be appreciated.

Best regards,
Javier.

On Fri, 26 Jan 2024 at 20:12, Brian Shaw <brian.shaw at noaa.gov> wrote:

> All
>
> Yes we are aware of this California Datum and it was developed by the California
> Spatial Reference Center <http://sopac-csrc.ucsd.edu/index.php/csrc/> (
> http://sopac-csrc.ucsd.edu/index.php/csrc/) at the request of CALTRANS.
> As suggested with California being on two tectonic plates with earthquakes
> that cause large displacements they needed to have a more updated datum
> than the time frame that NGS develops them.  I cannot specifically recall
> the earthquake that initiated this datum but I think it may have been one
> near Napa.  In my presentations I highlight the challenges California has
> due to earthquakes (China Lake in 2019 cause 6-10 feet of horizontal shift)
> and from subsidence (San Joaquin Valley USGS study showed up to 2 feet of
> subsidence in 16 months).  If interested here is a presentation I provided
> that has some of this information (
> https://geodesy.noaa.gov/web/science_edu/presentations_library/files/shaw_nsrs_mod_nsgic_20230928.pptx
> )
>
> Since Esri is based in California I suspect that is why they implemented
> it but this is not an NGS developed datum so I believe CSRC or CALTRANS
> would have to submit it to EPSG.
>
> I hope this helps
> Brian
>
> On 1/26/2024 11:02 AM, Even Rouault via PROJ wrote:
>
> Hi,
>
> interesting... It is known by ESRI as
> https://spatialreference.org/ref/esri/104024/ but AFAICS, there isn't any
> transformation registered in their database between this datum and other
> North American datums.
>
> There's a slide deck talking about it, where HTDP is mentionned (
> https://www.ngs.noaa.gov/TOOLS/Htdp/Htdp.html) :
> https://geodesy.noaa.gov/geospatial-summit/year-2019/files/martin-coordinates-moving.pptx
> , but I've the feeling the message might be that Californians found HTDP to
> not be faithful enough for their purpose. I dunno.. I guess our friends
> from NGS could confirm or infirm.
>
> I guess the reason for a separate datum is that part of California is
> anchored on a separate tectonic plate than the rest of N.A (or even the
> parts on the N.A. plate are subject to high deformation). Presumably this
> will be obsoleted by the NATRF2022 when it comes into life, and
> interestingly I found in
> https://casetext.com/statute/california-codes/california-public-resources-code/division-8-surveying-and-mapping/chapter-3-geodetic-datums-and-the-california-spatial-reference-network/section-8852-nad83-natrf2022-or-patrf2022
> that states "The official geodetic datum to which horizontal positions and
> ellipsoid heights are referenced within the State of California shall be
> NAD83, NATRF2022, or PATRF2022". Oh joy!
>
> Even
> Le 26/01/2024 à 18:24, Javier Jimenez Shaw via PROJ a écrit :
>
> Hi
>
> I discovered today that there is a datum in California called "CSRS Epoch
> 2017.50 (NAD83)"
> http://geoweb99.ucsd.edu/index.php/epoch2017/
> http://sopac-csrc.ucsd.edu/
>
> "CSRS Epoch 2017.50(NAD83) replaces the previous “CSRS Epoch 2011.00
> ITRF2005 NAD83(NSRS2007)” datum that included coordinates for 830 CSRN
> stations."
>
> I have not seen it before, so I guess there is no CRS using it in EPSG. (I
> do not find that datum in EPSG)
> How can it be used with PROJ?
>
> (Is it normal that some states use their own datum in the US? It is not
> enough with hundred of State Planes ;)
>
> Cheers,
> Javier.
>
> PS. Be careful with the acronyms:
> CRS: Coordinate Reference System
> CSRC: California Spatial Reference Center
> CSRS: California Spatial Reference System
> NAD83(CSRS): Canadian Spatial Reference System
>
> So "NAD83(CSRS)" and "CSRS (NAD83)" are not the same.
>
> .___ ._ ..._ .. . ._.  .___ .. __ . _. . __..  ... .... ._ .__
>
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>
>
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>
> --
> *************************************
> Brian Shaw
> Rocky Mountain Regional Advisor (CO, MT, WY)
> NOAA's National Geodetic Survey (NGS)
> Cell Phone # 240-988-6363
>
>
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